Add custom tag suggestion handler (#424)

lib/foundation/comic_source/comic_source.dart

@@ -184,6 +184,9 @@ class ComicSource {
 
   final HandleClickTagEvent? handleClickTagEvent;
 
+  /// Callback when a tag suggestion is selected in search.
+  final TagSuggestionSelectFunc? onTagSuggestionSelected;
+
   final LinkHandler? linkHandler;
 
   final bool enableTagsSuggestions;
@@ -259,6 +262,7 @@ class ComicSource {
     this.idMatcher,
     this.translations,
     this.handleClickTagEvent,
+    this.onTagSuggestionSelected,
     this.linkHandler,
     this.enableTagsSuggestions,
     this.enableTagsTranslate,

lib/foundation/comic_source/parser.dart

@@ -148,6 +148,7 @@ class ComicSourceParser {
       _parseIdMatch(),
       _parseTranslation(),
       _parseClickTagEvent(),
+      _parseTagSuggestionSelectFunc(),
       _parseLinkHandler(),
       _getValue("search.enableTagsSuggestions") ?? false,
       _getValue("comic.enableTagsTranslate") ?? false,
@@ -1057,6 +1058,19 @@ class ComicSourceParser {
     };
   }
 
+  TagSuggestionSelectFunc? _parseTagSuggestionSelectFunc() {
+    if (!_checkExists("search.onTagSuggestionSelected")) {
+      return null;
+    }
+    return (namespace, tag) {
+      var res = JsEngine().runCode("""
+          ComicSource.sources.$_key.search.onTagSuggestionSelected(
+            ${jsonEncode(namespace)}, ${jsonEncode(tag)})
+        """);
+      return res is String ? res : "$namespace:$tag";
+    };
+  }
+
   LinkHandler? _parseLinkHandler() {
     if (!_checkExists("comic.link")) {
       return null;

lib/foundation/comic_source/types.dart

@@ -44,5 +44,10 @@ typedef VoteCommentFunc = Future<Res<int?>> Function(
 typedef HandleClickTagEvent = PageJumpTarget? Function(
     String namespace, String tag);
 
+/// Handle tag suggestion selection event. Should return the text to insert
+/// into the search field.
+typedef TagSuggestionSelectFunc = String Function(
+    String namespace, String tag);
+
 /// [rating] is the rating value, 0-10. 1 represents 0.5 star.
 typedef StarRatingFunc = Future<Res<bool>> Function(String comicId, int rating);